1. Field of the Invention
This invention relates to an oil hydraulic pump which includes a suction connector provided at a suction port for sucking hydraulic operating fluid, and more particularly to a structure for attaching a suction connector to a suction port of an oil hydraulic pump.
2. Description of the Related Art
A typical one of convention oil hydraulic pumps is shown in FIGS. 4 and 5. Referring to FIGS. 4 and 5, the oil hydraulic pump shown includes a body b having a suction port 1 formed therein and having a seal groove 2 formed at a portion thereof around an opening of the suction port 1, and a seal 3 fitted in the seal groove 2.
A suction connector c is attached to the suction port 1. The suction connector c has a tubular portion 4 and has a flange portion 5 formed at an end of the tubular portion 4. A pair of bolt holes 6 are formed symmetrically at the opposite left and right end portions of the flange portion 5. Another pair of bolt holes 7 are formed in the body b in an aligned relationship with the bolt holes 6.
In order to attach the suction connector c to the body b, the seal 3 is fitted into the seal groove 2 first. Then, the suction connector c is placed so that the flange portion 5 thereof may be received by the seal 3, and a pair of bolts 8 are fitted into the bolt holes 6 and 7 to secure the suction connector c to the body b.
With the conventional pump described above, when to secure the suction connector c to the body b, the bolts 8 must be tightened with one hand while holding down the suction connector c with the other hand. Consequently, there is a problem that the attaching operation is unstable and the operation efficiency is very low.
Further, since a resilient force of a portion of the seal 3 corresponding to the interference acts in a direction to move the flange portion 5 away from the body b, each of the bolts 8 must be tightened with a sufficiently high tightening force to overcome the resilient force of the seal 3. Consequently, with the conventional pump described above, at least two bolts are required in order to obtain a balanced tightening force, and the number of bolts cannot be decreased any more.